Example embodiments of the inventive concepts relate to a memory device, and more particularly, to a nonvolatile memory device, a memory system, and a method of operating the memory system.
As a semiconductor memory device, a nonvolatile memory device includes a plurality of memory cells that store data in a nonvolatile manner. As an example of the nonvolatile memory device, a flash memory device may include multi-level cells that store 2 or more bits of data in each cell. The nonvolatile memory device may be used in portable phones, digital cameras, portable digital assistants (PDAs), mobile computer devices, stationary computer devices, and other devices.
In the nonvolatile memory device, a program operation may be performed a plurality of times on each wordline to store 2 or more bits of data in the multi-level cells. However, when an undesirable situation such as a sudden power-off (SPO) occurs, a program operation may be interrupted without being completed. In this case, it may be difficult to ensure data reliability.